This invention relates to drive trains for automobiles, and in particular to automobiles having automatic transmissions.
This invention also relates to vehicles having an internal combustion engine and auxiliary electric pneumatic or hydraulic engine drives. Such prior hybrid drive arrangements are disclosed in British Pat. No. 393,311, Swiss Pat. No. 222,098, and German Patent disclosure No. 2,133,485.
While it has been known in the prior art to make use of a hybrid arrangement of electric motor and internal combustion engine drive for a motor vehicle, none of the prior art hybrid drive arrangements suggest the use of this type of hybrid drive to eliminate the requirement for a torque converter in an automatic transmission, thereby providing a drive train arrangement which is highly efficient in fuel consumption.
According to the invention there is provided a drive train system which includes an internal combustion engine having a crankshaft which is connectable to a flywheel by a mechanically operated clutch. The flywheel is connected to the input of an automatic transmission, without the interposition of a hydrodynamic torque converter, which is usually provided. A starting motor, which is also known as a drive-up motor, preferably an electric motor, is provided for turning the flywheel. The vehicle is operated by making use of the starting motor to initially drive the vehicle, through the flywheel and the automatic transmission until a preselected rotational flywheel speed, or vehicle speed, is achieved. At this point the mechanical clutch is closed thereby connecting the flywheel to the crankshaft of the internal combustion engine, rapidly starting the internal combustion engine and thereafter the internal combustion engine can provide the principal portion of the power required for moving the vehicle. At this point, when power is being provided by the internal combustion engine, the vehicle starting motor can serve as a generator for use in recharging the vehicle battery. Thus the present invention goes beyond the mere use of both electrical and internal combustion engines for alternately propelling a motor vehicle, but makes use of this combination for the purpose of eliminating the hydro-dynamic torque converter usually used with an automatic transmission, and thereby improving the overall efficiency of operation of the vehicle.
It is a further feature of the invention that the flywheel is located on the side of the mechanical clutch which is away from the crankshaft of the engine. With this arrangement, when the clutch is opened the engine can be rapidly stopped, thereby preventing the unnecessary use of fuel by the engine during vehicle deceleration, coasting, or idling. The interal combustion engine is rapidly restarted upon the closing of this clutch using the energy which is stored in the flywheel.
With regard to the incorporation of an electric motor into the operation of the vehicle flywheel, German Patent disclosure No. 2,400,760 shows the integration of the flywheel with an electric motor which also serves as the starting motor. The flywheel is integrated into a clutch located between the internal combustion engine and the mechanical transmission. The starting motor is constructed as a disc rotor motor, however according to the reference, the flywheel is positioned on the same side of the mechanical clutch as the internal combustion engine crankshaft so that it is not possible to operate the drive with the engine and the flywheel decoupled.
It is therefore an object of the present invention to provide a new and improved drive train system for hybrid operation of a motor vehicle in a manner which eliminates the need, and consequent inefficiency, of the hydrodynamic torque converter conventionally used with an automatic transmission.